| 摘要 |
<p>An alarm system for detecting intrusion in a structure by means of acoustic emission, comprising an acoustic emission sensor (22) to be mounted on said structure so as to detect acoustic emission signals propagated through it, a processor (12, 14) for analysing the detected signal and determining if the detected signal exceeds a parameter threshold value, and an alarm unit (12) for providing an alarm signal if the detected signal exceeds the parameter threshold value. The alarm system further comprises an actuator for generating an acoustic emission test signal through the structure, which test signal is to be detected by the acoustic emission sensor (22). The processor (12, 14) is adapted to analyse the detected test signal to determine material properties of the structure, and select the parameter threshold value according to the determined material properties of the structure. The invention also relates to a method for detecting intrusion in a structure by means of acoustic emission.</p> |
